A power supplying apparatus may be capable of switching off a synchronous rectifier on a secondary side in advance by predicting a switching-on time on a primary side. The power supplying apparatus may include: a power converting unit switching power input to the primary side and transferring the power to the secondary side; and a synchronous rectifying unit formed on the secondary side, synchronized with the switching of the power converting unit to perform a rectification switching operation, thereby rectifying the power transferred from the power converting unit, and changing the rectification switching operation before a switching change point of the power converting unit depending on a preset timing.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A power supplying apparatus having a primary side and a secondary side electrically insulated from each other, comprising: a power converting unit switching power input to the primary side and transferring switched power to the secondary side; and a synchronous rectifying unit disposed on the secondary side, synchronized with the switching in the power converting unit to perform a rectification switching operation, thereby rectifying transferred power transferred from the power converting unit, and changing the rectification switching operation depending on a switch timing before a switching change point of the power converting unit, the synchronous rectifying unit including: a clock generating unit generating a clock signal depending on a point at which a switching operation of the power converting unit is changed from a switched off state to a switched on state; an off time determining unit determining a switching-off time of the rectification switching operation depending on the clock signal from the clock generating unit, the off time determining unit including: a voltage to current converter converting a preset reference voltage into a current: a triangle wave signal generator generating a triangle wave signal by charging the current in or discharging the current from the voltage to current converter depending on the clock signal; a voltage to voltage converter converting a voltage level of the triangle wave signal from the triangle wave signal generator depending on a preset resistance ratio; a hold voltage generator generating a hold voltage based on the triangle wave signal of which the voltage level is converted by the voltage to voltage converter; and a comparator comparing the hold voltage from the hold voltage generator and the voltage level of the triangle wave signal with each other to determine the switching-off time; and a driving unit driving a switching operation of a synchronous rectifier depending on the switching-off time of the off time determining unit.
2. The power supplying apparatus of claim 1 , wherein the synchronous rectifying unit changes the rectification switching operation from switching-on to switching-off before a point at which a switching operation of the power converting unit is changed from a switched off state to a switched on state.
3. The power supplying apparatus of claim 1 , wherein the clock generating unit senses a voltage level of the power transferred to the secondary side to generate the clock signal depending on the point at which the switching operation of the power converting unit is changed from the switched off state to the switched on state.
4. The power supplying apparatus of claim 3 , wherein the clock generating unit includes: a sensor sensing the voltage level of the power transferred to the secondary side; an RS latch performing a logic operation on a sensing result from the sensor; and a pulse generator generating a pulse signal at a rising edge point at which the switching operation of the power converting unit is changed from the switched off state to the switched on state depending on an operation result from the RS latch to output the clock signal.
5. The power supplying apparatus of claim 1 , wherein the triangle wave signal generator includes: a current mirror mirroring the current from the voltage to current converter; and a charging unit charging or a discharging unit discharging the current mirrored by the current mirror in or from a capacitor to generate the triangle wave signal.
6. A power supplying apparatus having a primary side and a secondary side electrically insulated from each other, comprising: a power converting unit switching power input to the primary side and transferring the power to the secondary side; and a synchronous rectifying unit formed on the secondary side, sensing a switching change point of the power converting unit to perform a rectification switching operation, thereby rectifying the power transferred from the power converting unit, and compensating for a delay of the sensed switching change point to change the rectification switching operation, the synchronous rectifying unit including: a clock generating unit generating a clock signal depending on a point at which a switching operation of the power converting unit is changed from a switched off state to a switched on state; an off time determining unit determining a switching-off time of the rectification switching operation depending on the clock signal from the clock generating unit, the off time determining unit including: a voltage to current converter converting a preset reference voltage into a current: a triangle wave signal generator generating a triangle wave signal by charging the current in or discharging the current from the voltage to current converter depending on the clock signal; a voltage to voltage converter converting a voltage level of the triangle wave signal from the triangle wave signal generator depending on a preset resistance ratio; a hold voltage generator generating a hold voltage based on the triangle wave signal of which the voltage level is converted by the voltage to voltage converter; and a comparator comparing the hold voltage from the hold voltage generator and the voltage level of the triangle wave signal with each other to determine the switching-off time; and a driving unit driving a switching operation of a synchronous rectifier depending on the switching-off time of the off time determining unit.
7. The power supplying apparatus of claim 6 , wherein the synchronous rectifying unit compensates for a delay of a point at which a switching operation of the power converting unit is changed from a switched off state to a switched on state to change the rectification switching operation from switching-on to switching-off.
8. The power supplying apparatus of claim 6 , wherein the clock generating unit senses a voltage level of the power transferred to the secondary side to generate the clock signal depending on the point at which the switching operation of the power converting unit is changed from the switched off state to the switched on state.
9. The power supplying apparatus of claim 8 , wherein the clock generating unit includes: a sensor sensing the voltage level of the power transferred to the secondary side; an RS latch performing a logic operation on a sensing result from the sensor; and a pulse generator generating a pulse signal at a rising edge point at which the switching operation of the power converting unit is changed from the switched off state to the switched on state depending on an operation result from the RS latch to output the clock signal.
10. The power supplying apparatus of claim 6 , wherein the triangle wave signal generator includes: a current mirror mirroring the current from the voltage to current converter; and a charging unit charging or a discharging unit discharging the current mirrored by the current mirror in or from a capacitor to generate the triangle wave signal.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
December 12, 2014
July 5, 2016
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